Voxel Sniper

VoxelSniper is the premier long range map editing tool for Minecraft.

This mod allows you to edit any block that you can see using an arrow (for replacing) and a gunpowder (for adding). It is best used by those with a strong attention to detail and fits a wide array of applications, from making detailed edits to structures with the snipe brush, to making massive terraforming jobs a breeze with some of the earth shattering soft selection tools.

Plugin Link:

https://dev.bukkit.org/projects/voxelsniper